Dynamic Foraging Patterns in Antarctic Humpbacks
Ben Weinstein
2017-04-28 08:56:16
## Source: local data frame [12 x 2]
##
## Animal max(timestamp, na.rm = T)
## (int) (time)
## 1 112699 2012-06-17 03:57:31
## 2 121207 2013-05-09 18:49:00
## 3 121208 2013-02-18 07:52:00
## 4 121210 2013-05-05 07:44:00
## 5 123224 2013-05-24 12:13:00
## 6 123232 2013-09-28 07:28:00
## 7 123236 2013-03-18 11:26:00
## 8 131127 2016-07-15 07:58:36
## 9 131130 2016-04-30 00:30:06
## 10 131132 2016-05-10 19:44:39
## 11 131133 2016-07-05 20:26:44
## 12 131136 2016-06-30 18:49:35
0.1 By Month
1 Correlated random walk
Process Model
\[ d_{t} \sim T*d_{t-1} + Normal(0,\Sigma)\] \[ x_t = x_{t-1} + d_{t} \]
1.1 Parameters
For each individual:
\[\theta = \text{Mean turning angle}\] \[\gamma = \text{Move persistence} \]
For both behaviors process variance is: \[ \sigma_{latitude} = 0.1\] \[ \sigma_{longitude} = 0.1\]
1.2 Behavioral States
\[ \text{For each individual i}\] \[ Behavior_1 = \text{traveling}\] \[ Behavior_2 = \text{foraging}\]
\[ \alpha_{i,1,1} = \text{Probability of remaining traveling when traveling}\] \[\alpha_{i,2,1} = \text{Probability of switching from Foraging to traveling}\]
\[\begin{matrix} \alpha_{i,1,1} & 1-\alpha_{i,1,1} \\ \alpha_{i,2,1} & 1-\alpha_{i,2,1} \\ \end{matrix}\]
With the probability of switching states:
\[logit(\phi_{traveling}) = \alpha_{Behavior_{t-1}}\]
\[\phi_{foraging} = 1 - \phi_{traveling} \]
1.3 Continious tracks
The transmitter will often go dark for 10 to 12 hours, due to weather, right in the middle of an otherwise good track. The model requires regular intervals to estimate the turning angles and temporal autocorrelation. As a track hits one of these walls, call it the end of a track, and begin a new track once the weather improves. We can remove any micro-tracks that are less than three days. Specify a duration, calculate the number of tracks and the number of removed points. Iteratively.
1.3.1 After filitering
How did the filter change the extent of tracks?
sink(“Bayesian/Multi_RW.jags”) cat(" model{
#Constants
pi <- 3.141592653589
#for each if 6 argos class observation error
for(x in 1:6){
##argos observation error##
argos_prec[x,1:2,1:2] <- argos_cov[x,,]
#Constructing the covariance matrix
argos_cov[x,1,1] <- argos_sigma[x]
argos_cov[x,1,2] <- 0
argos_cov[x,2,1] <- 0
argos_cov[x,2,2] <- argos_alpha[x]
}
for(i in 1:ind){
for(g in 1:tracks[i]){
## Priors for first true location
#for lat long
y[i,g,1,1:2] ~ dmnorm(argos[i,g,1,1,1:2],argos_prec[1,1:2,1:2])
#First movement - random walk.
y[i,g,2,1:2] ~ dmnorm(y[i,g,1,1:2],iSigma)
###First Behavioral State###
state[i,g,1] ~ dcat(lambda[]) ## assign state for first obs
#Process Model for movement
for(t in 2:(steps[i,g]-1)){
#Behavioral State at time T
phi[i,g,t,1] <- alpha_mu[state[i,g,t-1],Month[i,g,t]]
phi[i,g,t,2] <- 1-phi[i,g,t,1]
state[i,g,t] ~ dcat(phi[i,g,t,])
#Turning covariate
#Transition Matrix for turning angles
T[i,g,t,1,1] <- cos(theta[state[i,g,t]])
T[i,g,t,1,2] <- (-sin(theta[state[i,g,t]]))
T[i,g,t,2,1] <- sin(theta[state[i,g,t]])
T[i,g,t,2,2] <- cos(theta[state[i,g,t]])
#Correlation in movement change
d[i,g,t,1:2] <- y[i,g,t,] + gamma[state[i,g,t],Month[i,g,t]] * T[i,g,t,,] %*% (y[i,g,t,1:2] - y[i,g,t-1,1:2])
#Gaussian Displacement
y[i,g,t+1,1:2] ~ dmnorm(d[i,g,t,1:2],iSigma)
}
#Final behavior state
phi[i,g,steps[i,g],1] <- alpha_mu[state[i,g,steps[i,g]-1],Month[i,g,steps[i,g]-1]]
phi[i,g,steps[i,g],2] <- 1-phi[i,g,steps[i,g],1]
state[i,g,steps[i,g]] ~ dcat(phi[i,g,steps[i,g],])
## Measurement equation - irregular observations
# loops over regular time intervals (t)
for(t in 2:steps[i,g]){
# loops over observed locations within interval t
for(u in 1:idx[i,g,t]){
zhat[i,g,t,u,1:2] <- (1-j[i,g,t,u]) * y[i,g,t-1,1:2] + j[i,g,t,u] * y[i,g,t,1:2]
#for each lat and long
#argos error
argos[i,g,t,u,1:2] ~ dmnorm(zhat[i,g,t,u,1:2],argos_prec[argos_class[i,g,t,u],1:2,1:2])
}
}
}
}
###Priors###
#Process Variance
iSigma ~ dwish(R,2)
Sigma <- inverse(iSigma)
##Mean Angle
tmp[1] ~ dbeta(10, 10)
tmp[2] ~ dbeta(10, 10)
# prior for theta in 'traveling state'
theta[1] <- (2 * tmp[1] - 1) * pi
# prior for theta in 'foraging state'
theta[2] <- (tmp[2] * pi * 2)
##Move persistance
# prior for gamma (autocorrelation parameter) in state 1
#for each month
for (m in 1:Months){
#Intercepts
alpha_mu[1,m] ~ dbeta(1,1)
alpha_mu[2,m] ~ dbeta(1,1)
gamma[1,m] ~ dbeta(3,2) ## gamma for state 1
dev[m] ~ dbeta(1,1) ## a random deviate to ensure that gamma[1] > gamma[2]
gamma[2,m] <- gamma[1,m] * dev[m]
}
##Behavioral States
#Hierarchical structure across motnhs
#Variance
alpha_tau[1] ~ dt(0,1,1)I(0,)
alpha_tau[2] ~ dt(0,1,1)I(0,)
#Probability of behavior switching
lambda[1] ~ dbeta(1,1)
lambda[2] <- 1 - lambda[1]
##Argos priors##
#longitudinal argos precision, from Jonsen 2005, 2016, represented as precision not sd
#by argos class
argos_sigma[1] <- 11.9016
argos_sigma[2] <- 10.2775
argos_sigma[3] <- 1.228984
argos_sigma[4] <- 2.162593
argos_sigma[5] <- 3.885832
argos_sigma[6] <- 0.0565539
#latitidunal argos precision, from Jonsen 2005, 2016
argos_alpha[1] <- 67.12537
argos_alpha[2] <- 14.73474
argos_alpha[3] <- 4.718973
argos_alpha[4] <- 0.3872023
argos_alpha[5] <- 3.836444
argos_alpha[6] <- 0.1081156
}"
,fill=TRUE)sink()
## user system elapsed
## 313.671 3.234 56510.3851.4 Chains
## used (Mb) gc trigger (Mb) max used (Mb)
## Ncells 1490195 79.6 3205452 171.2 3205452 171.2
## Vcells 332757447 2538.8 609210048 4648.0 601969433 4592.7## used (Mb) gc trigger (Mb) max used (Mb)
## Ncells 1330363 71.1 3205452 171.2 3205452 171.2
## Vcells 43197765 329.6 487368038 3718.4 601969433 4592.7
1.5 Change in autocorrelation over time
2 Change in transition probabilities over time
2.1 Parameter Summary
## parameter par mean lower upper
## 1 alpha_mu alpha_mu[1,1] 0.80974467 0.718033670 0.88743661
## 2 alpha_mu alpha_mu[2,1] 0.18432108 0.105157153 0.29281197
## 3 alpha_mu alpha_mu[1,2] 0.87739367 0.802696831 0.93672939
## 4 alpha_mu alpha_mu[2,2] 0.12679749 0.064498206 0.20730521
## 5 alpha_mu alpha_mu[1,3] 0.86975061 0.773088035 0.93994914
## 6 alpha_mu alpha_mu[2,3] 0.08179307 0.042489490 0.13590807
## 7 alpha_mu alpha_mu[1,4] 0.74908180 0.601480996 0.94995402
## 8 alpha_mu alpha_mu[2,4] 0.17350926 0.049559723 0.33164349
## 9 alpha_mu alpha_mu[1,5] 0.75396995 0.601945827 0.88102617
## 10 alpha_mu alpha_mu[2,5] 0.07615231 0.032681773 0.13948078
## 11 alpha_mu alpha_mu[1,6] 0.69111511 0.479917954 0.86381503
## 12 alpha_mu alpha_mu[2,6] 0.17172694 0.061330279 0.32274025
## 13 gamma gamma[1,1] 0.91943745 0.869059019 0.96560491
## 14 gamma gamma[2,1] 0.17001743 0.027008133 0.32001713
## 15 gamma gamma[1,2] 0.82165383 0.767881529 0.88519502
## 16 gamma gamma[2,2] 0.08476265 0.007141743 0.20756066
## 17 gamma gamma[1,3] 0.77700814 0.693797183 0.86807351
## 18 gamma gamma[2,3] 0.09316598 0.007256009 0.23270703
## 19 gamma gamma[1,4] 0.88270542 0.730130324 0.97439356
## 20 gamma gamma[2,4] 0.09709066 0.004855736 0.32199482
## 21 gamma gamma[1,5] 0.75259925 0.597309716 0.90285379
## 22 gamma gamma[2,5] 0.39081676 0.223511359 0.56207378
## 23 gamma gamma[1,6] 0.84066572 0.689760784 0.96212763
## 24 gamma gamma[2,6] 0.40916347 0.130325658 0.66759611
## 25 theta theta[1] 0.02494263 0.008240810 0.04220695
## 26 theta theta[2] 3.09225319 2.866102956 3.31917406
3 Behavioral Prediction
3.1 Spatial Prediction
3.2 By individual
3.3 Autocorrelation in behavior
3.3.1 As single timeline
4 Simulated tracks
4.1 Behavioral description
4.1.1 Proportion of states by month
4.1.2 Distance between bouts
5 Behavior duration
## Source: local data frame [183 x 7]
## Groups: Animal, Track, Bout, phistate [183]
##
## Animal Track Bout phistate MonthF Days Month
## (dbl) (dbl) (int) (fctr) (dbl) (dbl) (fctr)
## 1 1 1 1 Traveling 1 0.60590278 January
## 2 1 2 1 Traveling 1 0.49538194 January
## 3 1 3 1 Traveling 1 0.64839120 January
## 4 1 4 1 Traveling 1 1.55869213 January
## 5 1 5 1 Traveling 1 0.65001157 January
## 6 1 6 1 Traveling 1 0.09663194 January
## 7 1 7 1 Traveling 2 0.98664352 February
## 8 1 8 1 Traveling 2 0.54603009 February
## 9 1 10 1 Traveling 2 0.92159722 February
## 10 1 11 1 Traveling 2 2.62181713 February
## .. ... ... ... ... ... ... ...## Source: local data frame [182 x 7]
## Groups: Animal, Track, Bout, phistate [182]
##
## Animal Track Bout phistate MonthF Days Month
## (dbl) (dbl) (int) (fctr) (dbl) (dbl) (fctr)
## 1 1 6 2 Area-restricted Search 1 2.1506597 January
## 2 1 9 1 Area-restricted Search 2 3.3496065 February
## 3 2 1 2 Area-restricted Search 2 0.1554977 February
## 4 2 1 4 Area-restricted Search 2 0.1646644 February
## 5 2 2 2 Area-restricted Search 3 11.1066551 March
## 6 2 2 4 Area-restricted Search 3 0.4727778 March
## 7 2 2 6 Area-restricted Search 4 2.4937847 April
## 8 2 2 8 Area-restricted Search 4 3.9760880 April
## 9 2 2 10 Area-restricted Search 4 0.9698958 April
## 10 2 2 12 Area-restricted Search 4 0.9459606 April
## .. ... ... ... ... ... ... ...## Source: local data frame [365 x 7]
## Groups: Animal, Track, Bout, phistate [365]
##
## Animal Track Bout phistate MonthF Days Month
## (dbl) (dbl) (int) (fctr) (dbl) (dbl) (fctr)
## 1 1 1 1 Traveling 1 0.60590278 January
## 2 1 2 1 Traveling 1 0.49538194 January
## 3 1 3 1 Traveling 1 0.64839120 January
## 4 1 4 1 Traveling 1 1.55869213 January
## 5 1 5 1 Traveling 1 0.65001157 January
## 6 1 6 1 Traveling 1 0.09663194 January
## 7 1 6 2 Area-restricted Search 1 2.15065972 January
## 8 1 7 1 Traveling 2 0.98664352 February
## 9 1 8 1 Traveling 2 0.54603009 February
## 10 1 9 1 Area-restricted Search 2 3.34960648 February
## .. ... ... ... ... ... ... ...
5.1 Proportion of time allocation
## Month Traveling Area-restricted Search PropF TotalTime
## 1 January 140.53505 136.10722 0.4919972 276.64227
## 2 February 219.13435 348.56628 0.6139966 567.70064
## 3 March 104.49234 196.61933 0.6529781 301.11167
## 4 April 49.41505 161.12559 0.7652945 210.54064
## 5 May 23.88398 82.92531 0.7763867 106.80929
## 6 June 16.20016 44.64175 0.7337335 60.841915.2 Number of bouts
6 Time spent in grid cell
6.1 All years
6.2 Add in sea ice
